Moistening mechanism for duplicating machines



Dec. 12, 1950 H. GERLACH 2,533,574

MOISTENING MECHANISM FOR DUPLICATING MACHINES Filed March 20, 1946 2 Sheets-Sheet l fyvvewfor H1199 Garza-MA Dec. 12, 1950 H. GERLACH 2,533,574

MOISTENING MECHANISM FOR DUPLICATING MACHINES Filed March 20, 1946 v 2 Sheets-Sheet 2 Patented Dec. 12, 1950 I MOISTENING MECHANISM FOR DUPLIOATING MACHINES Hugo Gerlach, Hendon, London, England, as-

signor to Block & Anderson Limited, London, England, a British company Application March 20, 1946, Serial No. 655,760 In Great Britain January 28, 1946 This invention relates to mechanisms for applying liquids to sheets of paper or the like. The problem of applying a liquid uniformly to the surface of a sheet of paper arises in hectographic copying machines in which each copy is taken from a hectographic original, or master sheet by bringing into contact with the master a copy sheet previously moistened with a liquid which is a solvent for the hectographic ink used in the preparation of the master. Insufficient damping results in poor copies, whereas excessive damping is detrimental to the master and reduces the total number of copies that can be obtained. The present invention has for its object to provide a liquid-applying mechanism which is capable of satisfying the requirements in hectographic copying machines.

According to the present invention, the mechanism for applying liquid to a sheet comprises a capillary pad arranged in contact with a liquid applying roller adapted to apply the liquid to a sheet passing between it and a further roller, the capillary pad being inclined downwardly away from the area of contact with the liquid applying roller, a pad supporting tray embracing the lower part of the pad, means for supplying liquid to the pad, and a drainage pipe attached to the pad tray at or near the lowermost part of the tray to withdraw any surplus liquid from the tray. Preferably the liquid is supplied to the capillary pad from a reservoir at a lower level by the actuation of a pump, and the drainage pipe discharges into the reservoir.

When used as a damping device for a hectographic copying machine, the applying roller and the co-operating roller of the mechanism according to the invention constitute a pair of feed rollers moistening and advancing the moistened copy sheet to the printing couple, consisting of a master drum and an impression roller. In this arrangement the liquid-applying roller may be driven from the rotation of the master drum to advance the sheet to the bight of the printing couple, the sheet being thereafter fed by the printing couple alone.

To facilitate the understanding of the present invention, a preferred embodiment as applied to a hectographic copyin machine will now be described with reference to the accompanying semidiagrammatic drawings, in which Fig. 1 is a side view, partly in section, of the essential components of the machine.

Fig. 2 is an enlarged plan view of the capillary pad and applying rollers, the left-hand portion having the damping roller omitted. Y

10 Claims. (01. 91-48) Fig. 3 is an enlarged perspective view of a detail.

The printing drum l is provided in known manner with means (not shown) for releasably securing on its peripheral surface a master sheet bearing in mirror script in hectographic ink the matter which it is desired to copy. The drum I is journalled in bearings in the side frames of the machine, and may be rotated manually by a hand crank or may be motor driven as in known hectographic copying machines. To take a copy, a copy sheet moistened with a solvent for the hectographic ink is fed between the printing drum 1 and the co-operating impression roller 2, which is urged against the printing drum with the ap-' propriate pressure. The mounting and arrange-. ment of the printing drum and co-operating pressure roller form no part of the present invention and consequently are not fully illustrated in the drawing, and will not be further described. In practice, any convenient mounting and arrangement can be adopted.

The present invention is concerned with the damping or liquid-applying mechanism, the pre-. ferred embodiment of which as shown inthe drawing will now be described.

The surface of the copy sheet which is to come into contact with the master sheet on the printing drum, i. e., the upper surface of the copy sheet in the arrangement according to Fig. 1, is mois-' tened by means of a damping roller 3, which is journalled in the side frames of the machine, the surface of which preferably consists of rubber. The damping liquid is applied to the surface of the roller 3 and thereby transferred to the copy sheet as the latter is fed between the damping roller 3 and a co-operating counter-roller 4, likewise journalled in the side frames of the machine. The shaft of the damping roller 3 carries a gear Wheel 5 for driving the damping roller 3 to feed the copy sheet to the bight of the printing couple I, 2. The gear wheel 5 meshes with a gear wheel 6 journalled in a rocking lever l which is mounted to pivot freely about the axis of the damping roller 3 within the limits imposed by stops 9, lil carried by the adjacent side frame of the machine. A spring 8 extending between the lever l and an anchor on the adjacent side frame of the machine, tends to urge the lever 1 towards the stop I 0. In this position of the lever l, the gear wheel 6 "is adapted to engage in a toothed segment H carried on one end of the printing drum l. The length of the toothed segment I l is such that the copy sheet is fed by the damping roller 3, and its counter roller 4 a distance sufficient to ensure the damping mechanism the feed table has an upwardly inclined feed section directing the leading edge of the sheet to the rollers 3, 4. The

cover plate 43 is preferably shaped as shown so relatively narrow gap between the lower surface of the upwardly inclined pad case 3'! and the upper surface of the inclined terminal section of the feed table 49.

On commencing copying operations, it may be necessary to prime the pad 36, and this can be effected either by rotating the drum l a suitable number of times, or by a corresponding number of manipulations of the control lever 29 between its extreme positions. During the running of the machine, the lever 29 is set in the position giving the desired supply of damping liquid, If an excessive amount of liquid is supplied to the pad 36 by the pump 25, 22, the surplus liquid is returned to the reservoir 23, and the maximum damping is that corresponding to the amount of liquid transferred to the roller 3 when the pad 36 is saturated, but actual flooding is avoided even when the pump is delivering too much liquid at each stroke.

I claim:

1. In a duplicating machine, means for applying solvent liquid to copy sheets comprising a roller against which said sheets are pressed during their delivery into the machine, a flat capillary pad, a rigid tray supporting said pad, stationary guide means for slidably mounting said tray and the supported capillary pad therein whereby such pad is inclined upwardly towards said roller and is movable in its own plane to present its uppermost longitudinal edge in abutting relationship to the surface of said roller, and means for resiliently urging said tray and the supported pad in the plane thereof towards said roller.

2. In a duplicating machine, means for applying solvent liquid. to copy sheets comprising a roller against which said sheets are pressed during their delivery into the machine, a fiat capillary pad, a rigid tray supporting said pad, means for slidably mounting said tray and the supported pad in a plane which is coincident with that of the pad and is upwardly inclined towards said roller, spring means for resiliently urging said tray bodily towards said roller whereby the uppermost longitudinal free edge of said pad is continuously pressed on to the peripheral surface of said roller, liquid distributor means overlying and spaced above the lower region of the uppermost side surface of said pad in said tray, a container for solvent liquid, and adjustable pumping means actuated during operation of the machine for delivering a regulable quantity of solvent liquid from said container to said liquid distributor means for discharge by gravity on to the lower region of said pad.

3. In a duplicating machine, means for applying solvent liquid to copy sheets comprising a pair of parallel and mutually contacting rollers through which such sheets pass, a fiat elongated capillary pad, a rigid tray supporting said pad, means for slidably mounting said tray and the supported capillary pad therein whereby such pad is inclined upwardly towards the underside of the uppermost roller just ahead of the bight of said pair of rollers, said pad and its supporting tray being movable in its own plane to present the uppermost longitudinal pad edge in substantially radial abutting relationship to the peripheral surface of said uppermost roller, means for as to form a funnel-like entrance leading to the resiliently urging said tray and its supported pad in its plane of permitted movement towards said roller, stationary liquid distributor means overlying and spaced above the lower region of the uppermost side surface of said'pad insaidv tray, a container for solvent liquid, means for delivering a regulable quantity of solvent liquid from said container to said stationary distributor means for discharge by gravity on to thelower region of said pad, and means for draining any surplus liquid at the lower end of said pad back to said container.

4. In a duplicating machine, a. main framework, a machine drive shaft journalled in said framework, means for applying solvent liquid to copy sheets comprising a pair of parallel and mutually contacting rollers through which such. sheets pass, a flat elongated capillary pad, a. rigid tray supporting and gripping said pad, means for mounting said tray and said supported pad in a readily detachable manner in fixed guideways secured to the frame of the machine whereby said pad lies in and is movable bodily in a plane which is inclined upwardly towards the under half surface of the uppermost roller of said pair of rollers so as to present the uppermost longitudinal edge of said pad to said uppermost roller just ahead of the bight of said rollers, spring means for constantly urging said tray and said pad therein along said fixed guideways towards said roller, an apertured liquid distributing pipe secured to fixed elements of the machine frame so as to lie spaced above the uppermost side surface of and parallel with the lower longitudinal edge of said pad, a container for solvent liquid, and mechanical pumping means actuated from said machine drive shaft for delivering solvent fluid from said container to said apertured distributing pipe for distribution by gravity on to the lower end of said pad.

5. In a duplicating machine, a 'main framework, a machine drive shaft journalled in said framework, means for applying solvent liquid to copy sheets comprising a pair of parallel and mutually contacting rollers through which said sheets are passed, a flat elongated capillary pad, a rigid tray supporting and gripping said pad, fixed upwardly inclined guideways secured at opposite transverse sides of the said framework, means on said rigid tray for engagement within said guideways whereby said tray and the pad supported therein lies in and is movable in a plane which is inclined upwardly towards the uppermost roller of said pair of rollers, spring urged means for constantly urging said tray and said supported pad upwardly along said guideways.

whereby the upper longitudinal edge of said pad is pressed resiliently against the peripheral sur face of said uppermost roller just ahead of the bight between the rollers, a first apertured liquidi distributing pipe rigidly mounted overlying the uppermost side surface of and parallel with the lower longitudinal edge of said pad, a second apertured liquid distributing pipe surrounding and concentric with said first pipe, a container for solvent liquid, and mechanical pumping means actuated from said machine drive shaft for delivering solvent fluid from said container through said first apertured distributing pipe into said second surrounding pipe and thence on to the lower end of said pad.

6. In a duplicating machine, a main framework, a machine drive shaft journalled on said framework, means for applying solvent liquid to copy sheets comprising a. pair of parallel and in lies in. and ,ismovable in-a plane which -is inclined upwardlytowardsthe uppermostroller of said ,paiz oi ro11e1-s, spring. urged-means for con-"- 1 riaaiaasaciiiigEm ty-through which saidsheets are, passed a flat elongated capillary pad,- I

eer s d tray, s ppo and r pp ai pa fined, upwardly inclinedv guideways at opposite--- transverse-sides ofitheqmachine, means on said 5 i .rigid tray for engagement within said-guideways whereby said tray-and the ad supported-therestantly urging said; trayaand said supported pad T, upwardly along said uidewayspwhereby the up- 11 per longitudinal edge of; saidrpad is pressed .resil- ,iently against the peripheralasurface of said upa permost roller,,a first liquid;-distributirigapipe rigidly secured, across thermachine above the" lQWBI 9nd of said pad ;and,previded-withr-a:plu-

,-,rality ofopenings in its; wall: remote from the ,pad, --a second liquid distribu-tingpipe surroundi ing said first pipe and having in its wall adjacent to the pad a plurality 0i liquid distributing open- I ,fromsaid machine drive shaft-for deliveringsoljvent fluid from said,:containerthrougha said first I apertured distributing pipe, into saidzsecond sur- ;ings of smaller size ,andgreater;number-than thoseoi said first pipe, a container-for solvent a liquid, and mechanicalpumping means. actuated 25 -rounding pipe and thence on to the lower end of ,work, a machine drive ,shaft journalled onnsaid .iramework, means-for applying solventiliquid tolcopysheet comprising a roller .against.- -which said pad. 1

7. In a duplicatingmachina-ra,mainframe- I said sheets arepressed duringtheir=1delivery.into

ithemachine, a fiatcapillaryepad, a rigid tray supporting said pad, means,- forslidablymounting .lirom the.lower r'egion of said..pad in said-stray,

, chine driveshaitpnce during each-operative-eycle f of the latter for delivering solventdiquid-irom said- 39 he slbrsra ro t e wergr s of sa d ,pa i mea riacliustineithe oper v 4 stroke of ,saidpumping means under the control said tray and the supported-,pad-in: a -plane,.-which is, upwardly inclined towards saidzroller spring means for t lflv r in said tray: bcdily to.- ,.;:wards. said roller, whereby the uppermost-longi- 40 tudin al;, .free edge of said pad is,,continuously pressed on to the peripheral suriacepf saidroller,

iq iid .-distribut r means. overlyingand'spaced a 'container ior. solvent lidiiid; meehanicaleiiecipceto izzn sws m ns actuate rfrom sa ontainerg isosa-id liquid distributommeans I (if the machine operator.

vent liquid evenly-along the longitudinal dimenprovided with a number of spaced apartholes, --such holes being relatively large in number and relatively small in size, compared with those of In a duplicatingmacl-iine, meansfor' applying-solvent liquid to bopy'sheets comprising a rollerrotatable about *a horizontal axis and against which said -copy 'sheets 'are 'pressed' during their delivery to the machine, afi'at andelongated capillary pad 'disposed'parallel with'the axis of said roller in a plane which is inclined up- --"Ward1'y'- towards said roller and with the uppermost longitudinal edge of said pad in'contact'with the-peripheral surface of said roller, 'means for distributing solvent liquid'evenly' along'the' longitudinal dimension of said padandidisposed aboveand in spaced relationship'to theupper most side surface of such pad at aregiontowards its lowermost edge and means for delivering a reg- -ulablequantity of s01v'ent"liquid'to said'liquid distributing means in timed relationship to the operation of themachine.

9.--A duplicating machine in'azccordanc *with claim 8 wherein said means for. distributing solsion of thep-ad comprises a first apertured' pipe rigidly mounted so as to overlie the lower "edge region of said "pad and a second apertured pipe surrounding said first pipe.

10. A duplicating machine in accordance with claim 9 wherein said first pipe is in fluid connection with said liquid delivering means and is provided a number of spaced apart holes and wherein said second pipe is sealed at each end and is said first pipe.

. HU GERLACH- F E CES C ED.

, The following references are of record in the file of patent} 

